Ratchet type impact tool



Dec. 8, 1953 o. J. SWENSON RATCHET TYPE IMPACT TOOL Filed July 11, 12550 2 Sheets-Sheet l INVENTOR. OSCAR J. SWE

QLSON ATT'YS Dec. 8, 1953 o. J. SWENSON RATCHET TYPE IMPACT TOOL 2 Sheets-Sheet 2 Filed July 11 1950 INVENTOR: OSCAR J. SWENSON BY Patented Dec. 8, 1953 1 UNITED STATES PATENT omen:

4 Claims. (01. 81-52.3)

This invention relates to hand-operated impact tools d, o a ti ul rl t a ha d -o era d tool for applying magnified force to threaded type fastenings. Y

The use of power driven impact tool to provide a magnified torque force for the driving of threaded type fastenings, such as nuts, bolts. c ew n t e l s alrea n wn- T mmon type of impact tool is one which employs a small electric motor as the driving force and is adapted to use in assembly line shops where one operator performs a single operation on a large number of nuts or bolts. Such a tool has limited use, however, because it must be used proximate to an electrical outlet and it is suitable for employment only on relatively small threaded fastenings. The tool has the further disadvantage of causing operator fatigue due to the vibration and impact which is transmitted to the operator.

It is an objector" this invention to provide a hand-operated tool which is capable of imparting a concentrated torsional force of considerably greater magnitude than the force that may be applied directly with a conventional hand! operated tool.

Another object of the invention is to provide a hand-Operated tool which is capable of imparting a torsional force of great magnitude in com bination with a ratchet element thereby to pe r' mit operation of the tool in a limited space.

A further object of the invention is to provide a hand-operated tool which is capable of imparting a concentrated torsional force of adjustable and controlled magnitude.

These and other objects and advantages of the invention will become more apparent from a con.- sideration of the following description taken in conjunction with the accompanying drawings in which:

Figure 1 is a side elevational view of a tool embodying the invention;

u e 2 is a n i ud na s ion l view through the rotor head of the tool;

Figure 3 is a partial sectional view taken along the lines 3- 3 of Figure l; and

Figure 4 is a sectional view of the head of the tool taken along a line corresponding to the lines 4-4 of Figure 3. v V

The present invention contemplates a handoperated impact tool embodying a torque magnifying feature. The tool may have a ratchet arrangement fo hs n m ted s ace andth tool a may a e a to ue on rollin or limltingieature.

Re e ing o t e. drawin s in. de ail a rotor I 2 comprising anannular surj face 2 and a top plate 3 is associated with a handle element 4 and a spring 5. The rotor lis made up of the body I 6 4;) into which is Set th DELW IS 1 Q1568 v which are pivoted at 5 and I0 respectively land which are held in exte ded position by the S rings andlZ. g Y

A ratchetwheel I3 'is adapted to fit within the annular opening in the rotor l. The teeth IQ, of the ratchet it are adapted to engage the leading edges ofthe pawls 1 and 8 in their advanced position. The ratchet [3 is carried on its bear.- ing surfaces {5 and I6 (Figure'3) within the trunnions ll and lfi which are integral partsoi the extensions 19 and 3 9, respectively, of the handle 4. end ofthe extension l9 and of its companion extension 39 are pivotally ass ch ated with the ratchet wheel 13. and with the rotor e the ommon is o thes woe men sj- The extension 15 has a pair of cam shaped surfaces 20 and 2| (Fig. 2) which are operatively associeied h ih eao h ed e efihei how mo -8 and which serve to disengage the pawls from the teeth I4 of theratchet wheel when relative rotational movement in theproperdirection takes place ween. he r or [and th h n l A f T ho l 1 and. 8 are'h t re esse i the o r body 6 am; are d vih their re p c ive sea s with, i eee imi e oiilat oh the de of he ea s y mace nd t com a on plate 3 3) Th shri es H aha 1i. h use e awls 1 o e 8 to a ag ins h teet t i he t h h el 13 d ri g kwiee ro tio of h ro r.

I but permi ff eroia ioh of or o 1 me co n e o k isedirect on lev a l wi the howls hl de s lient y o erihe rat h t e e s ir ne i mounted on the a hor part ,2 i 2 which torn is fixedly mou ed etwe h eh ensi h 19 o the hand e 4 nd. ts o res onoihe ehie si o i T e hhe eha 23 o s ir aching ishoe eo hdhe p eii e a h e ,e f; the $1 214 the arborw rt 22 i hr vehtzrela ver at ona m vemen e eeh the eating: and the a bo Th ou er end. 25 o the shrine. is ls hookeo a d ada ted ob seit dihtoihe s t 2 in th rotor bo y By h s arr n emen th r n 5. can h hhs t rea with a r ate o lessermfor e t e n e r tor and t e; andle 4 hr rotat on of the o rnar 2.? in a direc ion o. c use comes oh o he s rin 5 or decompress on he eo h arbor ort 22. he lookedt the, handle: 4 in any desired pos t. and at any inciden al- SPrin-g tehsioh bvtie t hihaa oeh sorew to i on he ea r ee oiihehahd v The rot r 3 is restrained from rotation under influence of the spring 5 by contact of the shoulder 21 against the extension IQ of the handle member 4. The graduated dial 28 imprinted on the extension IQ of the handle member 4 (Fig. 1) and the arrow 29 imprinted on the outer end of the arbor part 22 allow the operator to make reproducible settings f the tension on the spring at any desired value Within its range. These elements of the device make possible the torque adjusting and controlling feature of the invention.

Other details of the construction of the tool will be brought out by describing the function of the tool when applied to the tightening of a nut on a bolt. A pair of shaft extensions 31 and 32 (Fig.

3) are integrally associated with the ratchet wheel l3 and are adapted to receive a standard socket 33 of a socket wrench set. To operate the tool, the extension 3! is inserted into the matching square opening of the socket 33 and the socket is fitted over a nut 34 on a bolt 35. The handle 4 is then rotated clockwise about the axis of the shaft extension 3|. Alternatively the handle 4 may be operated in a reciprocating motion thereby employing the ratchet feature of the tool. In either mode of operation the unique features of the tool commence to function as soon as the nut becomes tight enough to offer resistance to further rotation. V

The resistance of the nut 34 is carried through the socket 33 to the shaft extension 31 and to the ratchet wheel l3. The ratchet is held in constant angular relationship with the nut and ceases rotating when the nut ceases. The rotor I likewise ceases rotation because the pawvls I and 8 are bearing against the teeth M of the ratchet l3. Continued rotation of the handle 4 now causes the spring 5 to be compressed and to absorb and to store the input energy of the handle stroke. When the handle has advanced sufficiently in axial relationship to the rotor I the cam surfaces and 21 encounter the leading edges of the pawls 1 and 8 and move them outwardly against the springs I0 and H until they clear the engaged teeth M of the ratchet wheel l3.

With the pawls no longer restraining it, the rotor I accelerates rapidly in a clockwise direction impelled by the energy previously stored in the spring 5 by the movement of the handle 4. The rate of rotation attained by the rotor l is many times greater than could be developed by direct application of manual force to the rotor. As the pawls i and 8 pass over the ratchet teeth from which they are disengaged, the springs H and 12 cause them to return to their original advanced position relative to the rotor. At this time the cam surfaces 20 and 2| will be in their original disengaged position relative to the rotor. The pawls 1 and 8 thus engage the next opposed pair of teeth l4 on the ratchet wheel l3 and the rotational energy contained in the swiftly moving rotor I is released suddenly as impact between the pawls I and 8 and the teeth of the ratchet wheel !3. In other words, the ratchet and pawl members also serve as anvil and hammer members, respectively. This impact gives a rotational impetus to the ratchet wheel l3 which is transmitted to'the extension 3! and through the engaging socket 33 to the nut 35. A large force has been brought to bear against the nut as a result of the action of the tool which has built up a large torsional force in the spring dur ing the rotation of the handle 4. e

If it should be necessary or desirable not to rotate the handle 4 in a complete circle, the han- 4 dle may be operated alternatively in a reciprocating motion. The counterclockwise portion of the reciprocated motion cycle will cause the rotor l to rotate counterclockwise along with the handle 4 because the extensions [9 and 39 of the handle engage the shoulder 21 of the rotor when counterclockwise motion has begun. Since the ratchet wheel 13 is being held stationary by its connection with the socket and nut, the pawls l and 3 drag over the ratchet teeth l4 and offer almost negligible resistance to movement of the rotor and the handle in counterclockwise direction. When the handle is again rotated in a clockwise direction, each of the pawls 1 and 8 will engage thenext ratchet teeth M in a clock- "wise direction from them. Further rotation of the handle in a clockwise direction will then produce repreated impacts against the nut in the manner described.

the opposite as described above for tightening the nut.

After operating the tool in the manner described for a time sufficient to cause it to impart several impacts to the nut, an equilibrium is reached between'the resistance offered by the nut to further rotation and the torsional force imparted to it by each additional impact. Under continued subjection to impacts of the same intensity, the nut will not be further rotated or tightened. Hence, the tool functions as a torque controlling or torque limiting wrench in the man ner hereafter described.

The initial tension of the spring 5 determines the amount of energy'which can be stored in it and released at each impact. It is a feature of the tool that the tension on the spring, and

thereby the force of the impacts, can be adjusted by a simple adjustment of the arbor parts in the tool. The arbor parts are manually rotated by means of suitable common wrenches in a suitable direction. The arbor parts may then be locked in the desired position by tightening the lock screw 3% which seats the shoulders 36 and 31 frictionally against the handle extensions 39 and IS. The degree of spring tension may be reproduced at each setting by simply aligning the arrow 29 with a predetermined number on the graduated dial 28. Hence, once the operator has determined a setting of the arrow and dial which will result in a certain torsional force upon operation of the tool, he -need only reset the device to the same number in order to achieve the same torsional force at any future time.

During normal operation of the device while imparting impacts of a very large torsional force to a piece of work, the operator feels no shock in the handle from the impacts. This, together with the torque magnifying properties of the device and with the reciprocating ratchet feature of the tool, greatly reduces operator fatigue incidental to tightening and loosening threaded type fastenin'gs. Bolts and 'nuts which would ordinarily require a four foot wrench plus an extension on the handle of the wrench may now be tightened or loosjenedby the simpleoperation of the present tool bya single operator.

The various features of the tool make it particularly useful inth'e operation of tightening f and loosening bolts andnuts of large size, e g1} the size used in high pressure "chemical equipment. The device is small and light in weight and can easily be operated in a limited space by an operator of normal strength.

The invention is hereby claimed as follows:

1. In a manually operable impact tool the combination of a rotatable tool head for engaging a threaded type fastening, manually actuated driving means, driving connections therebetween including ratchet and pawl members adapted to prevent relative movement of said driving means and said head in one direction and to allow relative movement thereof in another direction, a handle, cam means associated therewith for effecting separation of said ratchet and pawl members in response to movement of said handle when movement of said head is resisted by a predetermined force and spring means adapted to store up energy from the movement of said handle and to release said energy as impact energy upon the re-establishment of contact between said ratchet and pawl members.

2. In a manually operable impact tool the combination of a rotatable tool head for engaging a threaded type fastening, manually actuated driving means, driving connections therebetween including ratchet and pawl members adapted to prevent relative movement of said driving means and said head in one direction and to allow relative movement thereof in another direction, a handle, cam means associated therewith for effecting separation of said ratchet and pawl members in response to movement of said handle when -movement of said head is resisted by a predetermined force, spring means adapted to store up energy from the movement of said handle and to release said energy as impact energy upon the reestablishment of contact between said ratchet and pawl members, and means for adjusting the original tension on said spring means.

3. In a manually operable impact tool the combination of a rotatable tool head for engaging a threaded type fastening, manually actuated driving means, driving connection therebetween including ratchet and pawl members adapted to prevent relative movement of said driving means and said head in one direction and to allow relative movement thereof in another direction, a handle, cam means associated therewith for effecting separation of said ratchet and pawl members in response to movement of said handle when movement of said head is resisted by a predetermined force, spring means adapted to store up energy from the movement of said handle and to release said energy as impact energy upon the re-establishment of contact between said ratchet and pawl members, and means for adjusting and controlling the amount of torsional energy stored up in said driving means including arbor parts adjustable on said handle and operatively associated with one end of said spring means, said parts being adjustable to place said spring means under a predetermined tension.

4. A manually operable impact torsion tool comprising the combination of a tool head, driving means including ratchet and pawl means operatively associated to drive said head, energy storage means operative in response to manual operation to store up and release torsion energy in said driving means, cam means to cause disengagement of said ratchet and pawl means in response to manual operation when movement of said head is resisted by a predetermined force, and second energy storage means to cause said pawl means to reengage said ratchet means with impact in response to dissipation of energy stored in said first storage means, said ratchet and pawl means serving as anvil and hammer members, respectively, upon said reengagement.

OSCAR J. S'WENSON.

References Cited in the fiie of this patent UNITED STATES PATENTS Number Name Date 1,860,871 Pouliot May 31, 1932 2,122,693 Douglass Mar. 29, 1938 2,119,968 Shaff June '7, 1933 2,205,501 Sunnen June 25, 1940 2,271,803 Pfeiffer et al Feb. 3, 1942 2,342,783 Aron et a1 Feb. 29, 1944 2,378,956 Thorner June 26 1945 

